Title:
Concrete Q&A Acoustic Emission Monitoring
Author(s):
Publication:
Concrete International
Volume:
33
Issue:
10
Appears on pages(s):
80
Keywords:
DOI:
Date:
10/1/2011
Abstract:
The ACI publication, “Report on Corrosion and Repair of Grouted Multistrand and Bar Tendon Systems (ACI 423.8R-10),”1 describes two techniques for monitoring the strand in post-tensioned structures. One method allows monitoring of corrosion activity through changes in potential (voltage), but it requires that electrical contact is made with an electrically isolated tendon (the strand must be in a nonmetallic duct and the anchorage must be electrically insulated). Another method apparently allows monitoring of more conventional strand installations: Acoustic emission has been used in some cases to detect prestressing steel breakage in post-tensioning tendons. While these systems can be effective, they entail continuous monitoring of the structure to provide beneficial information. How can acoustic emission be used?